CD19 molecule(CD19) Homo sapiens Lymphocytes proliferate and differentiate in response to various concentrations of different antigens. The ability of the B cell to respond in a specific, yet sensitive manner to the various antigens is achieved with the use of low-affinity antigen receptors.This gene encodes a cell surface molecule which assembles with the antigen receptor of B lymphocytes in order to decrease the threshold for antigen receptor-dependent stimulation. [provided by RefSeq, Jul 2008]
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Function:
Functions as coreceptor for the B-cell antigen receptor complex (BCR) on B-lymphocytes. Decreases the threshold for activation of downstream signaling pathways and for triggering B-cell responses to antigens . Activates signaling pathways that lead to the activation of phosphatidylinositol 3-kinase and the mobilization of intracellular Ca(2+) stores . Is not required for early steps during B cell differentiation in the blood marrow . Required for normal differentiation of B-1 cells (By similarity). Required for normal B cell differentiation and proliferation in response to antigen challenges . Required for normal levels of serum immunoglobulins, and for production of high-affinity antibodies in response to antigen challenge .
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Cellular Localization:
Cell membrane ; Single-pass type I membrane protein . Membrane raft ; Single-pass type I membrane protein .
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Tissue Expression:
Expressed on activated B-cells, macrophages and dendritic cells.
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Research Areas:
>>Cell adhesion molecules ;
>>Toll-like receptor signaling pathway ;
>>Intestinal immune network for IgA production ;
>>Type I diabetes mellitus ;
>>Autoimmune thyroid disease ;
>>Systemic lupus erythematosus ;
>>Rheumatoid arthritis ;
>>Allograft rejection ;
>>Graft-versus-host disease ;
>>Viral myocarditis